1. Field of the Invention
The present invention relates to a brushless DC electric motor, and in particular, to a brushless DC electric motor having a flux concentrating member thereon.
2. Description of the Prior Art
A brushless DC electric motor uses an array of magnetically responsive sensors, such as Hall Effect devices, to generate the commutation control signals that switch current among the motor's field windings. The sensors are triggered by the proximal passage of the permanent magnets carried on the rotor.
The Hall Effect device, whether of the latching or non-latching type, requires that a magnetic flux of a sufficient density impinge thereon. Moreover, for most effective operation, the flux must be oriented within some close angular range of perpendicularity with respect to the face of the Hall Effect device. Unless these considerations of sufficient flux density and proper flux orientation are met there is a possibility of erroneous switching of the device.
In view of the foregoing it is believed to be advantageous to provide a flux concentrating arrangement for conducting magnetic flux to and through the magnetic sensors in a brushless DC motor.